Table 1.

24 h ambulatory impedance-pH measurement

	Off PPI	On PPI	Normal
% time pH < 4.0
Total	50	27	< 4.0%
Upright	45	10	< 4.7%
Supine	57	55	< 2.0%
Supragastric belches
Total	188	17	Absent
Symptom episodes
Severe belching	4		-
Heartburn	5		-
% time with hiccup	> 60%	> 60%	Absent

PPI: Proton pump inhibitor.